Method of repairing coke-oven walls



July 19, 1949. s. H. KIMMEL 2,476,305

METHOD OF REPAIRING COKE OVEN WALLS Filed on. 9, 1945 !2: PAIR Seaman-4* E2 tcrsnfizcnomi INVENTOR Swvsu-z ro/v H. KIM/76L.

ATToRNEY Patented July 19, 1949 METHOD OF REPAIRING COKE-OVEN WALLS Singleton H. Kimmel, Pittsburgh, Pa., assignor to Koppers Company, Inc., Pittsburgh, Pa., a corporation of Delaware Application October 9, 1945, Serial No. 621,283

2 Claims. i

' This invention relates to the repairing of coke ovens. More particularly the invention relates to an expansion joint used in the repairing of byproduct coke ovens.

The coke oven structure including the ovens and regenerators used therewith are preferably built of silica refractory brick or shapes. These silica refractories have a peculiar expansion characteristic in that they expand rapidly as they are heated from atmospheric temperature up to a temperature of approximately 1500. peratures above 1500 F. there is practically no further expansion of the silica shapes as the temperature is increased up to 3000 F. This expansion characteristic is quite advantageous in coke oven structures because in the normal operation of the coke oven, the oven and regenerator structures are constantly held at a temperature above 1500 F. so that there is a comparatively small amount of contraction and expansion of the structures when they are in a heated condition.

The coking ovens themselves are open at each end. These openings are closed by doors when coal is being coked within the ovens. These doors are removed when the cokeis to be pushed out of the ovens and at this time the refractory shapes close to the ends of the ovens often become cooled below 1500 F. so that these sections of the ovens are subjected to expansion and contraction which often causes the refractory shapes to deteriorate and disintegrate.

The repair of disintegrated refractory walls preferably is carried out while the coke oven structure is heated because it is not practicable to cool down a coke oven battery for repairs. When the refractory shapes are heated from atmospheric temperature up to approximately 1500 0. these shapes expand to substantially larger dimensions than when they are cold. It is necessary, therefore, when repairing heated walls to join the smaller cold shapes with the heated shapes so that the oven wall will assume a uniform condition when all-of the wall becomes heated to a uniform temperature.

The primary object of the present invention is to provide an expansion joint construction by which a hot oven wall may be repaired to restore it to normal operating condition.

Another object of the invention is to provide a method of repairing hot coke oven walls which are built out of silica refractory shapes.

A further object of the invention is to provide a method of repairing a silica wall structure by which an expansion joint is provided to take care of changing heat conditions prevalent at the ends of the coke ovens.

With these and other objects in view, the invention consists in the improved method of repairing coke ovens hereinafter described and particularly defined in the appended claims.

The various features of the invention are illustrated in the accompanying drawings in which:

Figure 1 is a vertical sectional view of a coke oven structure showing the application of the present method of repairing coke oven walls to the walls of the coke oven and heating flues;

Figure 2 is a vertical sectional view of a coke oven wall taken on the line 11-11 of Figure l: and

Figure 3 is a perspective detail view showing refractory shapes used for wall construction of the coke oven and heating flues.

The method of repairing coke oven walls of the present invention is illustrated in the drawings as applied to the repairing of the walls IU of a coke oven l2. Between each of the ovens F2 are positioned heating fiues l4 so that the walls I0 which form the coke oven also form the heating flues. The walls I 0 are usually built of refractory silica shapes which are special shapes such as illustrated in Figure 3, with grooves I6 and tongues [8 by which the shapes may be interlocked in the wall. composed of crushed fused silica brick, 25% silica clay and 25% raw ganister or quartzite is used for cementing the bricks together in the 'wall. This cement is highly siliceous and has substantially the same expansion characteristics as the silica shapes. The tongue-and-groove construction prevents the leakage of gas from the coke oven into the heating fiues and likewise prevents the leakage of combustion gases from the heating flues into the coke oven.

When the coke oven structure is originally built, the coke ovens are closed with doors at each end and the structure is slowly heated to bring the temperature of the oven battery up to the desired operating temperature. During the heating operation the entire refractory structure undergoes expansion. The steel work and buckstays of the oven battery are built to make provision for this expansion and the whole structure is constructed to provide tight ovens and heating flues when the temperature is up to the normal operating condition.

In accordance with the type of coke being made the temperatures which are maintained in the heating flues l4 may vary from 2000 F. to 2750 F. The temperature prevailing in the middle of A common cement which is acvaaos charges of coal which goes into the oven. The

oven walls normally are maintained above the temperature of 1500 F. When the doors are taken ofi of both ends of the oven to push the coke out of the oven, the cold air from the exterior penetrates a short distance into the oven so that the walls adjacent the doors become cooled below 1500 F. and this causes considerable expansion and contraction that tends to disintegrate the refractory walls. It is ofen necessary to repair refractory walls adjacent the oven l fe application of the present invention to the repair of coke oven walls is shown more particularly in Figure 2 which shows a repair section and a section of the wall as originally built. When the oven walls are to be repaired heating of the fines Id at each side of the oven i2 is discontinued and a bulkhead is placed within the oven back of the section to be repaired, in order to shield the workmen fromthe heat of the walls. It is to be understood that the adjoining ovens and fiues are being heated at the time that a special oven is being isolated for repairs. The old refractory shapes are then torn out and new refractory shapes are built in, to replace and repairthe wall. The new refractory shapes have substantially the same composition, size and shape as the shapes in the heated wall in order to make a wall of uniform construction. The shapes are laid in courses 22 using the normal coke oven cement of the type described above between most of the courses, but as hereinafter explained, a difierent type of cement is employed between selected courses. When the courses are laid in the wall the tongues and grooves on the shapes of the new shapes being placed in the wall are made to engage the tongues and grooves in the shapes.of the heated wall.

It will be understood that in view of the fact that the silica'refractories have considerable expansion when heated, the cold shapes incorporated in the repaired portion of a wall are substantially smaller in dimensions than the heated shapes in the original wall. Therefore in laying up the courses of new shapes, as illustrated in Figure 2, the courses of shapes will not align with the courses of shapes in the hot wall. Furthermore, because of the expansion of the silica shapes on heating, if the repaired section of the wall were built up solid with cold silica shapes bound together with silica cement of the type normally employed, the repaired portion of the wall would expand so much on heating that it would lift the roof of the oven chamber and thus seriously damage the battery. To provide for the differences in dimensions. of the courses of shapes in the hot and cold portions of the wall a compressible cement 24 is usedbetween each group of five courses of the new shapes. The compressible cement 24 is preferably made of vermiculite or expanded mica which is mixed with silica clay in the proportion of 60 to 80% vermiculite to 40 to 20% clay. However, the invention is not limited to these specific proportions and the compressible cement may include a larger proportion of expanded clay, and, for example, may be composed of 70% clay and expanded mica. This compressible cement layer preferably has a thickness such that when the cold shapes are heated to the temperature oi. the hot shapes, or preferably heated to a temperature of approximately 1500 F. the courses of the cold shapes will align with the courses of the hot shapes, and so that the vertical height of the courses of silica shapes and intervening layers of cement in the repaired section of the wall will not be materially greater after this portion of the wall is heated than it is when constructed.

The cement described above has the particular feature of providing a gas-tight cemented joint which is formed at the time that the vermiculite has been compressed into the clay and hardened by the expansion of the shapes under heat. This joint is an effective gas-tight joint and still is capable of expanding under heat changing conditions.

Depending upon the size of the shapes and the condition of the oven walls a layer of the compressible cement may be required between groups I of three of four courses of shapes. It has been found in practice, however, that a compressible joint for every five courses gives a very satisfactory wall construction. By having the compressible joint in the section adjacent the door opening, the wall is given more freedom for ever occurring expansion and contraction without putting strain on the refractory shapes which tends to disintegrate them.

After the oven and heating flue walls have been repaired, the bulkheads are withdrawn. The oven doors are inserted in the end of the oven and then the walls are slowly brought up to operating temperature to expand the cold brick to operating condition. This heating operation is carried on slowly in order to avoid undue strain to the oven structure. After the oven wall temperature has become quite uniform throughout, the repaired oven may be put into operation.

The preferred form of the invention having been thus described, what is claimed as new is:

1. In a method of repairing the walls of a horizontal coke oven in which there are horizontal coking chambers each of which has at each side a vertically flued heating wall formed of courses of silica shapes bound with silica cement, said method comprising the steps of removing shapes from the deteriorated portion of a vertical wall so as to leave portions of the original oven structure below and above the removed wall portion,

and While the portions of the'oven structure adjacent said deteriorated wall portion are maintained at a relatively high temperature so that the silica shapes present therein are in their expanded condition reconstructing the removed wall portion with relatively cold silica shapes of substantially the same composition and shape as the shapes in the remainder of the wall, said reconstruction comprising the steps of laying on.

the portion of the oven structure below the removed wall portion courses of silica shapes bound with cement so as to completely fill the area beneath the portion of the oven structure above the removed wall portion, the cement employed between most of said courses being a siliceous cement of substantially the same type as is employed in the remainder of the wall, the cement employed between the remainder of said courses being a compressible cement of refractory material composed of from 60% to 80% of expanded mica and 40% to 20% of siliceous clay and being of such thickness that on heating of the reconstructed portionof the wall the silica shapes therein may expand without materially increasing the vertical dimension of said reconstructed wall portion.

2. In a method of repairing the walls of a horizontal coke oven in which there are horizontal coking chambers each of which has at each side a vertically fiued heating wall formed of courses of silica shapes bound with silica cement, said method comprising the steps of removing shapes from the deteriorated portion of a vertical wall so as to leave portions of the original oven structure below and above the removed wall portion, and while the portions of the oven structure adjacent said deteriorated wall portion are maintained at a relatively high temperature so that the silica shapes present therein are in their expanded condition reconstructing the removed wall portion with relatively cold silica shapes of substantially the same composition and shape as the shapes in the remainder of the wall, said rethe portion of the oven structure below the re-' moved wall portion courses of silica shapes bound with cement so as to completely fill the area beneath the portion of the oven structure above the removed wall portion, the cement employed between most of said courses being a siliceous cement of substantially the same type as is employed in the remainder of the wall, the cement employed between the remainder of said courses being a compressible cement of refractory material composed of expanded mica and clay and wherein the clay is at least 20% and the expanded mica is at least 30% and being of such thickness that on heating of the reconstructed portion of the wall the silica shapes therein may expand without materially increasing the vertical dimension of said reconstructed wall portion,

SINGLETON H. KIMMEL.

REFERENCES CITED The following references are of record in the file of this patent:

construction comprising the steps of laying on UNITED STATES PATENTS Number 

